1. Field of the Invention
The present invention relates to a sample container turning apparatus and, more particularly, to a sample container turning apparatus for turning a sample container (or specimen container) containing a sample (or specimen) such as blood to be analyzed, on the axis of the container with a view to reading the code of a bar code label adhering to the container, or mixing and homogenizing the sample in the container.
2. Description of the Prior Art
In the prior art, there is an automatic analyzing system for analyzing a specimen by conveying a plurality of specimen containers to a specimen analyzing apparatus. In this system, there has been widely used a specimen rack for holding the specimen containers generally vertically so as to hold and convey the containers.
The specimen container held by the specimen rack may sometimes be desired to be turned on the generally vertical axis of the container. This occurs, for example, when the specimen in the container is agitated so that it may be homogenized or when the code of the bar code label adhering to the specimen container is read out. The following examples are known in the prior art as the specimen container turning apparatus for turning the specimen container held on the specimen rack on the generally vertical axis of the container.
One example is a specimen container turning apparatus which is constructed such that there is vertically movably provided a rotary member made rotatably on a vertical axis, such that the rotary member is lowered from above a specimen container closed with a cap, onto the upper face of the cap of the specimen container, and such that the rotary member is then rotated. In the specimen container turning apparatus thus constructed, the rotary member transmits its rotational force to the specimen container by a frictional force which is generated by a pressure contact between the rotary member and the cap of the specimen container.
Another example is a specimen container turning apparatus which is constructed like the aforementioned turning apparatus excepting that the rotary member has its lower face bulged or recessed whereas the specimen container has its upper face recessed or bulged to be fitted on the lower face of the rotary member. In the specimen container turning apparatus thus constructed, the rotary member transmits its rotational force to the specimen container by the fitting contacts of the recessed and bulged portions of the rotary member and the specimen container.
In the former specimen container turning apparatus, when the rotary member is forced to contact the upper face of the cap of the specimen container, the frictional force is generated between the bottom wall of the specimen container and the container holding face of the specimen rack. The frictional force thus generated may act as a resistance at the turning time to make the turn of the specimen container insufficient.
This problem grows especially serious when a rubber sheet or the like is applied to the container holding face of the specimen rack so as to prevent any unnecessary turn of the specimen container when the code of the bar code label adhering to the specimen container held by the specimen rack is read out. In order to solve this problem, a high torque has to be given to the drive source used for the rotary member.
In the latter specimen container turning apparatus, on the other hand, in order to fit the rotary member and the specimen container snugly, it is necessary to provide a mechanism for positioning the rotary member and the specimen container precisely. For this necessity, there arises a problem that the turning apparatus is enlarged in size and the mechanism thereof becomes more complicated.
The present invention has been conceived in view of the background thus far described and an object of the invention is to provide a small-sized simple sample container turning apparatus capable of transmitting the turning force reliably from a drive source to a sample container even the drive source used has a low torque.